January 30, 2013

This shows clouds over the Pacific. Credit: Shang-Ping Xie

Global warming from greenhouse gases affects rainfall patterns in the world differently than that from solar heating, according to a study by an international team of scientists in the January 31 issue of Nature. Using computer model simulations, the scientists, led by Jian Liu (Chinese Academy of Sciences) and Bin Wang (International Pacific Research Center, University of Hawaii at Manoa), showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.

The team examined global precipitation changes over the last millennium and future projection to the end of 21st century, comparing natural changes from solar heating and volcanism with changes from man-made greenhouse gas emissions. Using an atmosphere-ocean coupled climate model that simulates realistically both past and present-day climate conditions, the scientists found that for every degree rise in global temperature, the global rainfall rate since the Industrial Revolution has increased less by about 40% than during past warming phases of the earth.

Why does warming from solar heating and from greenhouse gases have such different effects on global precipitation?

"Our climate model simulations show that this difference results from different sea surface temperature patterns. When warming is due to increased greenhouse gases, the gradient of sea surface temperature (SST) across the tropical Pacific weakens, but when it is due to increased solar radiation, the gradient increases. For the same average global surface temperature increase, the weaker SST gradient produces less rainfall, especially over tropical land," says co-author Bin Wang, professor of meteorology.

But why does warming from greenhouse gases and from solar heating affect the tropical Pacific SST gradient differently?

"Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable," explains lead-author Jian Liu. "The increased atmospheric stability weakens the trade winds, resulting in stronger warming in the eastern than the western Pacific, thus reducing the usual SST gradient—a situation similar to El Niño."

Solar radiation, on the other hand, heats the earth's surface, increasing the usual temperature difference between the surface and the top of the atmosphere without weakening the trade winds. The result is that heating warms the western Pacific, while the eastern Pacific remains cool from the usual ocean upwelling.

"While during past global warming from solar heating the steeper tropical east-west SST pattern has won out, we suggest that with future warming from greenhouse gases, the weaker gradient and smaller increase in yearly rainfall rate will win out," concludes Wang.

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Wow .. weird..The make a model which shows that the rainfall increases would be different, but theres little indication that they then went out and checked actual rain fall in the two periods. A model is a theory, it needs to be compared to measurement to be tested, they seem to have only completed half the work.

Then theres this gem:"adding heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable" so this model contradicts the current idea that CAGW leads to instability in the atmosphere (extreme weather); they cant BOTH be right! Perhaps people would trust climate science more as a discipline if they werent always contradicting each other with warm/cold/wet/dry predicitions.And what happened to the warming? MET now forecasts 20 years of no warming despite doubling of CO2 output... maybe the theory is broken?

"Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable,"

What a bunch of crap.

Heating, weather by increased solar radiance, or green house absorption, are both forms of solar heating. And, there's no evidence the atmosphere is more evenly heated by CO2 over solar radiance. In fact, quite the opposite:

Then theres this gem:"adding heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable" so this model contradicts the current idea that CAGW leads to instability in the atmosphere (extreme weather); they cant BOTH be right!

"Shells from the 10th to 12th centuries (early MCA) were collected from well-stratified horizons, which accumulated in Viking shell and fish middens at Quoygrew on Westray in the archipelago of Orkney, Scotland."

Thus the article is not about Global Temperatures but Regional Temperatures in Scotland during the MWP.

But Gregor is not interested in the truth. He is interested in perpetuating a lie in order to further his ideological goals, so he dishonestly compares current global temperatures with possible temperatures in Scotland.

What a bunch of crap. Heating, weather by increased solar radiance, or green house absorption, are both forms of solar heating. And, there's no evidence the atmosphere is more evenly heated by CO2 over solar radiance. In fact, quite the opposite: "When carbon dioxide gets into the thermosphere, it acts as a coolant, shedding heat via infrared radiation."

Ubavontuba. If that was the case, we would be experiencing significantly cooler temperatures. Might I also remind you that the temperature of the surface of Venus is well over 400 degrees celcius, because of the thick CO2 atmosphere, acting like a blanket, trapping the sun's heat. It's basic science. The global rise in temperatures is in direct correlation with the beginning of the industrial era.

so this model contradicts the current idea that CAGW leads to instability in the atmosphere (extreme weather); they cant BOTH be right! Perhaps people would trust climate science more as a discipline if they werent always contradicting each other with warm/cold/wet/dry predicitions.

Instability in the atmosphere refers to the lapse rate with height. The greater the LR the more unstable it is ( the ability of air to rise upwards ). Solar energy would impact the surface more and give rise to greater instability whereas CO2 would absorb/emit long wave radiation from the atmosphere itself, causing a small amount of warming aloft, so decreasing the LR, making it more stable.It has become more apparent that a warming world shifts it's heat around in more complex ways. If you are prepared to accept that the ENSO oscillation affects global weather, then it is not much of a stretch to realise that, say, reduced Arctic ice would have an effects impacting the NH Autumn/winter weather.

Hah, that's stupid. I have no connection with Vendicar, whatsoever. I just happen to agree with him on most of what he says. And, what is this "medieval warm period" that you keep referring to on all of these articles? It's a total crock of nonsense. I notice that your website reference was to a German site. I tried to go back to the main page, to see what data sources were available, but the site wasn't working.

The bods at skeptical science are the masters of the cherry pick though I hadn't noticed they were Medieval Wam period deniers now. I wasn't referring to you as VD's sock puppet but vendicarE who used to be Vendicar decarian or some such. I'll post the link again. The MWP has been confirmed world wide in around 1,000 papers. I don't think you can call that a cherry pick.

And here is the MWP projectMedieval Warm Period Project"Was there a Medieval Warm Period? YES, according to data published by 1133 individual scientists from 652 research institutions in 46 different countries ... and counting! Our latest Medieval Warm Period Record comes from Lake Montcortès, Northeast Spain. To access the entire Medieval Warm Period Project's database,"

Check an unbiased source; from http://en.wikiped...m_Period we read "The Medieval Warm Period (MWP), Medieval Climate Optimum, or Medieval Climatic Anomaly was a time of warm climate in the North Atlantic region that may also have been related to other climate events around the world during that time ..."

Wikipedia's an unbiased source is it? You've never heard of William Connolley then? He's a member of the greens in the UK and a founder of the propaganda site realclimate."All told, Connolley created or rewrote 5,428 unique Wikipedia articles. His control over Wikipedia was greater still, however, through the role he obtained at Wikipedia as a website administrator, which allowed him to act with virtual impunity. When Connolley didn't like the subject of a certain article, he removed it — more than 500 articles of various descriptions disappeared at his hand. When he disapproved of the arguments that others were making, he often had them barred — over 2,000 Wikipedia contributors who ran afoul of him found themselves blocked from making further contributions."http://wattsupwit...rmation/There are no unbiased sources in this debate. All we have is peer reviewed science.

Wikipedia's an unbiased source is it? You've never heard of William Connolley then? He's a member of the greens in the UK and a founder of the propaganda site realclimate.

Of what material relevance to the cited article?

There are no unbiased sources in this debate.

Only if you argue that opinions have standing equal to empirical facts, which would be illogical.

All we have is peer reviewed science.

Balderdash. Not only has "peer review" given us the beliefs that Earth was flat and the center of the universe, but you conveniently reject peer reviewed conclusions when they do not well comport with your desired conclusions.

You referenced wikipedia and I pointed out that it was a poor choice and not to be trusted. Extraordinary claims require extraordinary proof and when activists are willing to subvert Wikipedia and the IPCC for there own political ends we need to be doubly careful. Models are not evidence of anything yet and are mere curiosities until they start getting some of their predictions right. As to your wild assertion about which science I accept may I remind you of the scientific method. You make an hypothesis which you then try and disprove. It's the evidence that disproves the hypothesis which is the most important.http://www.aitse....-or-not/

You referenced wikipedia and I pointed out that it was a poor choice and not to be trusted.

Non-responsive. Of what material relevance your claim to the specific article cited?

Extraordinary claims require extraordinary proof and when activists are willing to subvert Wikipedia and the IPCC for there own political ends we need to be doubly careful.

Not only are no extraordinary claims here made, but such claims require no more than the customary standard of proof.

Models are not evidence of anything yet and are mere curiosities until they start getting some of their predictions right.

Irrelevant to the matter at hand.

As to your wild assertion about which science I accept may I remind you of the scientific method. You make an hypothesis which you then try and disprove. It's the evidence that disproves the hypothesis which is the most important.

Now, gregor1, returning to the matter at hand, stop evading by mis-direction.

The facts remains that, not only was the MWP NOT GLOBAL in scope, but it is irrelevant to the current warming trend and its causes. Presently observed effects are not constrained to being the results of previously observed causes.

In other words, you are so driven to attack at all costs that you are unable to distinguish friend from foe.

"Peer" does not refer to scientists alone; scientists as we today know them did not exist throughout all times. And, just as some are today not independent voices, but agents of big business, so too for the past, when many pursued their interests at the pleasure of royalty and church.

@ Vendicar & deepsand - whoa you two.Vendicar he didn't say anything aggrievous enough to justify such a harsh response.Deepsand, I think you misunderstand peer review as it applies to scientific rigor over the past 300 or so years. There was no peer review in the time of Columbus, there was, at best, the consensus opinion of the masses. Peer review now is the soul of the scientific method. It is the means by which claims are checked and verified. It is the best system to verify science that we currently have.

I fully understand what peer review is today, and how that of the past differed. My point is that it has changed, and that gregor1 chooses to ignore it when he finds it convenient to his purpose of the moment. Examples of past beliefs were offered solely for the purpose of demonstrating that invoking the phrase "peer review" out of context was without meaning, and attempt by gregor1 at deflecting legitimate criticism of his claims.

Vendicar failed to grasp that, and engaged in an unwarranted ad hominem attack against one who is allied with him in defending against the AGW denialists.

So you deepsand are a Medieval warm period "denialist?" Do you have any peer reviewed links, other than Mann's infamous hockey stick that show that it didn't happen despite the 900 or so papers that show that it did. Calling people names is fun but it's not science. And, by the way, don't play with the trolls. They're not on anybodies 'side'. They're just trolls.

@ deepsand - Ok fair enough. Your comment about peer review struck me as a bit odd because of how it was worded, and apparently I wasn't the only one! :)

gregor, well he is a special case. He likes to hook his wagon to whatever his buddy at WUWT's flavour of the day happens to be. Lately, that has been putting up 15 year old data and pretending like its something new. His posts SEEM intellegent, until you look beyond the surface.

And I'm saying there are now hundreds of papers that clearly show it was worldwide and evident on every continent including Antarctica. The majority of those papers show it was warmer than today. Your rusted on position appears to be such that if someone cites a legitimate study that has been linked to on a site that you , in you wisdom, have decided is a "denier" site then the paper is invalid by association. This is more a reflection on you than anyone else.http://pages.scie...iod.html

This study demonstrates rather clearly, that changes in atmospheric CO2 are not tracking changes in human emissions. Changes in global atmospheric CO2 are lagging 11–12 months behind changes in global sea surface temperature. Changes in global atmospheric CO2 are lagging 9.5–10 months behind changes in global air surface temperature. Instead of it, the changes in ocean temperatures explain a substantial part of the observed changes in atmospheric CO2 since January 1980. Together with heat content anomaly, this analysis again supports my geothermal theory of global warming, caused with decay of radioactive elements inside of Earth crust and marine water, initiated with neutrinos from dark matter cloud at the galactic plane.

Historical variations of temperatures may be affected with these changes as well. In this context it may be significant, that the distribution of neutrinos around Sun may be affected with mutual positions of planets - we do observe the positive correlations of some climatic cycles with periodicity of Jupiter and Neptune planets. So yes, some of climatic variations in the history could be explained with this model too.

Inert uncharged particles that only very rarely interact with other particles

In some cases they can interact very strongly and we even have theory for it based on resonance of neutrino oscillations within atom nuclei. In AWT the neutrinos are chameleon particles and low energy neutrinos are absorbed with atom nuclei even more than the cold neutrons.

yours are neutrinos with very special properties that make them different from those emitted in vast quantities for our Sun

So far we can observe mostly the solar neutrinos only, because they're of relatively high energy. But the dark matter is formed mostly with very cold neutrinos, which are in thermal equilibrium with CMBR fluctuations. Their velocity is lower than the escape velocity from Sun, so that these neutrinos tend to cummulate around Sun like sorta thick atmosphere, pervading substantial portion of solar system. I do presume, that the hot neutrinos from Sun don't contribute to this atmosphere, they're rather doing this neutrino atmosphere unstable and they're disturbing it with polar neutrino jets, so that the solar activity correlates negatively with dark matter density around Sun. It can be measured with speed of decay of various radioactive elements inside of spaceprobes flying around Sun.

Just remember that the people who keep the original temperature data are the very people who profit the most from this AGW hoax. These historical records have been altered on a regular basis in order to prove that their worthless climate models are correct.These are the persons who get paid by the world governments to distribute the propaganda used to get you to agree to give up your freedoms and wealth. The climate "science" establishment has sold out all of their scientific values for a few sheckels of government grants.

..dark matter is formed mostly with very cold neutrinos ..Pure speculation.

It plays well with many observations of dark matter. String theory is pure speculation as well and it has no observational support yet.

I speculate that DM consists of grains of solid hydrogen approximately 1,000 atoms in size and positively charged through surface ionization.

The tiny atom clusters would have a very large pressure (consider the Young-Laplace equation). You would need a very high concentration of free hydrogen atoms in the cosmic space for to keep such a clusters stable.

I fully understand what peer review is today, and how that of the past differed. My point is that it has changed, and that gregor1 chooses to ignore it when he finds it convenient to his purpose of the moment. Examples of past beliefs were offered solely for the purpose of demonstrating that invoking the phrase "peer review" out of context was without meaning, and attempt by gregor1 at deflecting legitimate criticism of his claims.

Vendicar failed to grasp that, and engaged in an unwarranted ad hominem attack against one who is allied with him in defending against the AGW denialists.